-- Knowledge Platform schema migration
-- Migration id: 0022_logical_document_revisions
-- Dialect: postgres

ALTER TABLE "deletion_jobs" DROP CONSTRAINT IF EXISTS "deletion_jobs_target_ck";
ALTER TABLE "deletion_jobs" ADD CONSTRAINT "deletion_jobs_target_ck" CHECK (
  "target_type" IN ('knowledge_space', 'source', 'document_asset', 'logical_document')
  AND (
    ("target_type" = 'source' AND "delete_mode" IN ('keep', 'cascade') AND "name_challenge_digest" IS NULL)
    OR ("target_type" = 'knowledge_space' AND "delete_mode" = 'cascade' AND "name_challenge_digest" IS NOT NULL)
    OR ("target_type" IN ('document_asset', 'logical_document') AND "delete_mode" = 'cascade' AND "name_challenge_digest" IS NULL)
  )
);
ALTER TABLE "deletion_tombstones" DROP CONSTRAINT IF EXISTS "deletion_tombstones_target_ck";
ALTER TABLE "deletion_tombstones" ADD CONSTRAINT "deletion_tombstones_target_ck"
  CHECK ("target_type" IN ('knowledge_space', 'source', 'document_asset', 'logical_document'));

CREATE UNIQUE INDEX IF NOT EXISTS "sources_space_id_uq"
  ON "sources" ("knowledge_space_id", "id");

CREATE UNIQUE INDEX IF NOT EXISTS "document_compilation_attempts_scope_id_uq"
  ON "document_compilation_attempts" ("tenant_id", "knowledge_space_id", "id");

CREATE TABLE IF NOT EXISTS "logical_documents" (
  "id" UUID PRIMARY KEY NOT NULL,
  "tenant_id" VARCHAR(255) NOT NULL,
  "knowledge_space_id" UUID NOT NULL,
  "source_id" UUID,
  "provider_item_id" VARCHAR(1024),
  "provider_item_digest" CHAR(64),
  "title" TEXT NOT NULL,
  "status" VARCHAR(16) NOT NULL,
  "deletion_job_id" UUID,
  "deleting_at" TIMESTAMPTZ,
  "active_revision" INTEGER,
  "row_version" INTEGER NOT NULL,
  "system_metadata" JSONB NOT NULL,
  "user_metadata" JSONB NOT NULL,
  "created_at" TIMESTAMPTZ NOT NULL,
  "updated_at" TIMESTAMPTZ NOT NULL,
  CONSTRAINT "logical_documents_status_ck"
    CHECK ("status" IN ('pending', 'ready', 'failed', 'deleting')),
  CONSTRAINT "logical_documents_deletion_lifecycle_ck"
    CHECK (
      ("status" = 'deleting' AND "deletion_job_id" IS NOT NULL AND "deleting_at" IS NOT NULL)
      OR ("status" <> 'deleting' AND "deletion_job_id" IS NULL AND "deleting_at" IS NULL)
    ),
  CONSTRAINT "logical_documents_active_revision_ck"
    CHECK ("active_revision" IS NULL OR "active_revision" > 0),
  CONSTRAINT "logical_documents_row_version_ck"
    CHECK ("row_version" >= 0),
  CONSTRAINT "logical_documents_provider_identity_ck"
    CHECK (
      (
        "source_id" IS NULL
        AND "provider_item_id" IS NULL
        AND "provider_item_digest" IS NULL
      )
      OR (
        "source_id" IS NOT NULL
        AND "provider_item_id" IS NOT NULL
        AND "provider_item_digest" ~ '^[a-f0-9]{64}$'
      )
    ),
  FOREIGN KEY ("tenant_id", "knowledge_space_id")
    REFERENCES "knowledge_spaces" ("tenant_id", "id")
    ON DELETE CASCADE
);

CREATE UNIQUE INDEX IF NOT EXISTS "logical_documents_scope_id_uq"
  ON "logical_documents" ("tenant_id", "knowledge_space_id", "id");
CREATE UNIQUE INDEX IF NOT EXISTS "logical_documents_provider_item_uq"
  ON "logical_documents" ("provider_item_digest")
  WHERE "provider_item_digest" IS NOT NULL;
CREATE INDEX IF NOT EXISTS "logical_documents_space_cursor_idx"
  ON "logical_documents" ("tenant_id", "knowledge_space_id", "created_at", "id");

CREATE TABLE IF NOT EXISTS "document_revisions" (
  "tenant_id" VARCHAR(255) NOT NULL,
  "knowledge_space_id" UUID NOT NULL,
  "document_id" UUID NOT NULL,
  "revision" INTEGER NOT NULL,
  "document_asset_id" UUID NOT NULL,
  "document_asset_version" INTEGER NOT NULL,
  "compilation_attempt_id" UUID,
  "expected_active_revision" INTEGER,
  "expected_document_row_version" INTEGER NOT NULL,
  "content_hash" VARCHAR(64) NOT NULL,
  "mime_type" VARCHAR(255) NOT NULL,
  "size_bytes" BIGINT NOT NULL,
  "state" VARCHAR(16) NOT NULL,
  "system_metadata" JSONB NOT NULL,
  "created_at" TIMESTAMPTZ NOT NULL,
  "activated_at" TIMESTAMPTZ,
  PRIMARY KEY ("tenant_id", "knowledge_space_id", "document_id", "revision"),
  CONSTRAINT "document_revisions_revision_ck" CHECK ("revision" > 0),
  CONSTRAINT "document_revisions_asset_version_ck" CHECK ("document_asset_version" > 0),
  CONSTRAINT "document_revisions_expected_active_ck"
    CHECK ("expected_active_revision" IS NULL OR "expected_active_revision" > 0),
  CONSTRAINT "document_revisions_expected_row_version_ck"
    CHECK ("expected_document_row_version" >= 0),
  CONSTRAINT "document_revisions_size_ck" CHECK ("size_bytes" >= 0),
  CONSTRAINT "document_revisions_hash_ck" CHECK ("content_hash" ~ '^[0-9a-f]{64}$'),
  CONSTRAINT "document_revisions_state_ck"
    CHECK ("state" IN ('candidate', 'active', 'superseded', 'failed')),
  CONSTRAINT "document_revisions_activation_ck"
    CHECK (
      ("state" IN ('active', 'superseded') AND "activated_at" IS NOT NULL)
      OR ("state" IN ('candidate', 'failed') AND "activated_at" IS NULL)
    ),
  FOREIGN KEY ("tenant_id", "knowledge_space_id", "document_id")
    REFERENCES "logical_documents" ("tenant_id", "knowledge_space_id", "id")
    ON DELETE CASCADE,
  FOREIGN KEY ("knowledge_space_id", "document_asset_id", "document_asset_version")
    REFERENCES "document_assets" ("knowledge_space_id", "id", "version")
    ON DELETE RESTRICT
);

CREATE INDEX IF NOT EXISTS "document_revisions_asset_idx"
  ON "document_revisions" (
    "tenant_id",
    "knowledge_space_id",
    "document_asset_id",
    "document_asset_version"
  );
CREATE UNIQUE INDEX IF NOT EXISTS "document_revisions_compilation_attempt_uq"
  ON "document_revisions" ("tenant_id", "knowledge_space_id", "compilation_attempt_id")
  WHERE "compilation_attempt_id" IS NOT NULL;
CREATE INDEX IF NOT EXISTS "document_revisions_history_idx"
  ON "document_revisions" ("tenant_id", "knowledge_space_id", "document_id", "revision" DESC);

DO $$
BEGIN
  IF NOT EXISTS (
    SELECT 1
    FROM pg_constraint
    WHERE conname = 'logical_documents_active_revision_fk'
      AND conrelid = 'logical_documents'::regclass
  ) THEN
    ALTER TABLE "logical_documents"
      ADD CONSTRAINT "logical_documents_active_revision_fk"
      FOREIGN KEY ("tenant_id", "knowledge_space_id", "id", "active_revision")
      REFERENCES "document_revisions" (
        "tenant_id",
        "knowledge_space_id",
        "document_id",
        "revision"
      )
      DEFERRABLE INITIALLY DEFERRED;
  END IF;
END
$$;

CREATE TABLE IF NOT EXISTS "document_revision_chunks" (
  "id" UUID PRIMARY KEY NOT NULL,
  "tenant_id" VARCHAR(255) NOT NULL,
  "knowledge_space_id" UUID NOT NULL,
  "document_id" UUID NOT NULL,
  "document_revision" INTEGER NOT NULL,
  "parent_chunk_id" UUID,
  "ordinal" INTEGER NOT NULL,
  "token_count" INTEGER NOT NULL,
  "text" TEXT NOT NULL,
  "system_metadata" JSONB NOT NULL,
  "user_metadata" JSONB NOT NULL,
  "created_at" TIMESTAMPTZ NOT NULL,
  UNIQUE ("tenant_id", "knowledge_space_id", "document_id", "document_revision", "id"),
  CONSTRAINT "document_revision_chunks_ordinal_ck" CHECK ("ordinal" >= 0),
  CONSTRAINT "document_revision_chunks_tokens_ck" CHECK ("token_count" >= 0),
  FOREIGN KEY ("tenant_id", "knowledge_space_id", "document_id", "document_revision")
    REFERENCES "document_revisions" (
      "tenant_id",
      "knowledge_space_id",
      "document_id",
      "revision"
    )
    ON DELETE CASCADE,
  FOREIGN KEY (
    "tenant_id",
    "knowledge_space_id",
    "document_id",
    "document_revision",
    "parent_chunk_id"
  ) REFERENCES "document_revision_chunks" (
    "tenant_id",
    "knowledge_space_id",
    "document_id",
    "document_revision",
    "id"
  ) ON DELETE CASCADE
);

CREATE UNIQUE INDEX IF NOT EXISTS "document_revision_chunks_ordinal_uq"
  ON "document_revision_chunks" (
    "tenant_id",
    "knowledge_space_id",
    "document_id",
    "document_revision",
    "ordinal"
  );
CREATE INDEX IF NOT EXISTS "document_revision_chunks_cursor_idx"
  ON "document_revision_chunks" (
    "tenant_id",
    "knowledge_space_id",
    "document_id",
    "document_revision",
    "id"
  );

CREATE TABLE IF NOT EXISTS "document_chunk_state_changes" (
  "id" UUID PRIMARY KEY NOT NULL,
  "tenant_id" VARCHAR(255) NOT NULL,
  "knowledge_space_id" UUID NOT NULL,
  "document_id" UUID NOT NULL,
  "document_revision" INTEGER NOT NULL,
  "chunk_id" UUID NOT NULL,
  "enabled" BOOLEAN NOT NULL,
  "state" VARCHAR(16) NOT NULL,
  "compilation_attempt_id" UUID NOT NULL,
  "candidate_publication_id" UUID,
  "candidate_fingerprint" VARCHAR(86),
  "created_at" TIMESTAMPTZ NOT NULL,
  "activated_at" TIMESTAMPTZ,
  CONSTRAINT "document_chunk_state_changes_state_ck"
    CHECK ("state" IN ('candidate', 'active', 'superseded', 'failed')),
  CONSTRAINT "document_chunk_state_changes_activation_ck"
    CHECK (
      ("state" IN ('active', 'superseded') AND "activated_at" IS NOT NULL)
      OR ("state" IN ('candidate', 'failed') AND "activated_at" IS NULL)
    ),
  CONSTRAINT "document_chunk_state_changes_candidate_pair_ck"
    CHECK (
      ("candidate_publication_id" IS NULL AND "candidate_fingerprint" IS NULL)
      OR ("candidate_publication_id" IS NOT NULL AND "candidate_fingerprint" IS NOT NULL)
    ),
  FOREIGN KEY (
    "tenant_id",
    "knowledge_space_id",
    "document_id",
    "document_revision",
    "chunk_id"
  ) REFERENCES "document_revision_chunks" (
    "tenant_id",
    "knowledge_space_id",
    "document_id",
    "document_revision",
    "id"
  ) ON DELETE CASCADE
);

CREATE UNIQUE INDEX IF NOT EXISTS "document_chunk_state_changes_candidate_uq"
  ON "document_chunk_state_changes" (
    "tenant_id",
    "knowledge_space_id",
    "document_id",
    "document_revision",
    "chunk_id",
    "candidate_publication_id"
  );
CREATE UNIQUE INDEX IF NOT EXISTS "document_chunk_state_changes_attempt_uq"
  ON "document_chunk_state_changes" (
    "tenant_id", "knowledge_space_id", "compilation_attempt_id"
  );
CREATE INDEX IF NOT EXISTS "document_chunk_state_changes_active_idx"
  ON "document_chunk_state_changes" ("chunk_id", "state", "activated_at", "id");

CREATE TABLE IF NOT EXISTS "document_settings_revisions" (
  "tenant_id" VARCHAR(255) NOT NULL,
  "knowledge_space_id" UUID NOT NULL,
  "document_id" UUID NOT NULL,
  "revision" INTEGER NOT NULL,
  "settings" JSONB NOT NULL,
  "state" VARCHAR(16) NOT NULL,
  "created_by_subject_id" VARCHAR(255) NOT NULL,
  "created_at" TIMESTAMPTZ NOT NULL,
  "activated_at" TIMESTAMPTZ,
  PRIMARY KEY ("tenant_id", "knowledge_space_id", "document_id", "revision"),
  CONSTRAINT "document_settings_revisions_revision_ck" CHECK ("revision" > 0),
  CONSTRAINT "document_settings_revisions_state_ck"
    CHECK ("state" IN ('candidate', 'active', 'superseded', 'failed')),
  CONSTRAINT "document_settings_revisions_activation_ck"
    CHECK (
      ("state" IN ('active', 'superseded') AND "activated_at" IS NOT NULL)
      OR ("state" IN ('candidate', 'failed') AND "activated_at" IS NULL)
    ),
  FOREIGN KEY ("tenant_id", "knowledge_space_id", "document_id")
    REFERENCES "logical_documents" ("tenant_id", "knowledge_space_id", "id")
    ON DELETE CASCADE
);

CREATE TABLE IF NOT EXISTS "document_settings_heads" (
  "tenant_id" VARCHAR(255) NOT NULL,
  "knowledge_space_id" UUID NOT NULL,
  "document_id" UUID NOT NULL,
  "active_revision" INTEGER NOT NULL,
  "row_version" INTEGER NOT NULL,
  "updated_at" TIMESTAMPTZ NOT NULL,
  PRIMARY KEY ("tenant_id", "knowledge_space_id", "document_id"),
  CONSTRAINT "document_settings_heads_revision_ck" CHECK ("active_revision" > 0),
  CONSTRAINT "document_settings_heads_row_version_ck" CHECK ("row_version" >= 0),
  FOREIGN KEY ("tenant_id", "knowledge_space_id", "document_id", "active_revision")
    REFERENCES "document_settings_revisions" (
      "tenant_id",
      "knowledge_space_id",
      "document_id",
      "revision"
    )
    ON DELETE RESTRICT
    DEFERRABLE INITIALLY DEFERRED
);

CREATE TABLE IF NOT EXISTS "document_reindex_attempts" (
  "id" UUID PRIMARY KEY NOT NULL,
  "tenant_id" VARCHAR(255) NOT NULL,
  "knowledge_space_id" UUID NOT NULL,
  "document_id" UUID NOT NULL,
  "document_revision" INTEGER NOT NULL,
  "settings_revision" INTEGER NOT NULL,
  "expected_settings_head_revision" INTEGER NOT NULL,
  "state" VARCHAR(16) NOT NULL,
  "active_slot" INTEGER,
  "compilation_attempt_id" UUID NOT NULL,
  "candidate_publication_id" UUID,
  "candidate_fingerprint" VARCHAR(86),
  "row_version" INTEGER NOT NULL,
  "error_code" VARCHAR(64),
  "error_message" TEXT,
  "created_at" TIMESTAMPTZ NOT NULL,
  "updated_at" TIMESTAMPTZ NOT NULL,
  "completed_at" TIMESTAMPTZ,
  CONSTRAINT "document_reindex_attempts_state_ck"
    CHECK ("state" IN ('queued', 'running', 'succeeded', 'failed', 'canceled')),
  CONSTRAINT "document_reindex_attempts_active_slot_ck"
    CHECK ("active_slot" IS NULL OR "active_slot" = 1),
  CONSTRAINT "document_reindex_attempts_row_version_ck" CHECK ("row_version" >= 0),
  CONSTRAINT "document_reindex_attempts_expected_settings_head_revision_ck"
    CHECK ("expected_settings_head_revision" > 0),
  CONSTRAINT "document_reindex_attempts_lifecycle_ck"
    CHECK (
      ("state" IN ('queued', 'running') AND "active_slot" = 1 AND "completed_at" IS NULL)
      OR
      ("state" IN ('succeeded', 'failed', 'canceled') AND "active_slot" IS NULL AND "completed_at" IS NOT NULL)
    ),
  CONSTRAINT "document_reindex_attempts_candidate_pair_ck"
    CHECK (
      ("candidate_publication_id" IS NULL AND "candidate_fingerprint" IS NULL)
      OR
      ("candidate_publication_id" IS NOT NULL AND "candidate_fingerprint" IS NOT NULL)
    ),
  FOREIGN KEY ("tenant_id", "knowledge_space_id", "document_id", "document_revision")
    REFERENCES "document_revisions" (
      "tenant_id",
      "knowledge_space_id",
      "document_id",
      "revision"
    ) ON DELETE RESTRICT,
  FOREIGN KEY ("tenant_id", "knowledge_space_id", "document_id", "settings_revision")
    REFERENCES "document_settings_revisions" (
      "tenant_id",
      "knowledge_space_id",
      "document_id",
      "revision"
    ) ON DELETE RESTRICT
);

CREATE UNIQUE INDEX IF NOT EXISTS "document_reindex_attempts_active_uq"
  ON "document_reindex_attempts" (
    "tenant_id",
    "knowledge_space_id",
    "document_id",
    "active_slot"
  );
CREATE INDEX IF NOT EXISTS "document_reindex_attempts_cursor_idx"
  ON "document_reindex_attempts" (
    "tenant_id",
    "knowledge_space_id",
    "document_id",
    "created_at",
    "id"
  );

CREATE INDEX IF NOT EXISTS "document_compilation_attempts_space_cursor_idx"
  ON "document_compilation_attempts" (
    "tenant_id",
    "knowledge_space_id",
    "created_at",
    "id"
  );

-- Compatibility bridge: every pre-existing DocumentAsset remains addressable as a logical
-- document with one immutable active revision. New provider imports may instead attach additional
-- assets as later revisions of a stable logical document.
INSERT INTO "logical_documents" (
  "id",
  "tenant_id",
  "knowledge_space_id",
  "source_id",
  "provider_item_id",
  "title",
  "status",
  "active_revision",
  "row_version",
  "system_metadata",
  "user_metadata",
  "created_at",
  "updated_at"
)
SELECT
  asset."id",
  space."tenant_id",
  asset."knowledge_space_id",
  NULL,
  NULL,
  asset."filename",
  CASE
    WHEN asset."parser_status" = 'parsed' THEN 'ready'
    WHEN asset."parser_status" = 'failed' THEN 'failed'
    ELSE 'pending'
  END,
  NULL,
  0,
  jsonb_build_object(
    'legacyDocumentAssetId', asset."id"::text,
    'provenance', asset."metadata"
  ),
  '{}'::jsonb,
  asset."created_at",
  COALESCE(asset."updated_at", asset."created_at")
FROM "document_assets" asset
JOIN "knowledge_spaces" space ON space."id" = asset."knowledge_space_id"
ON CONFLICT ("id") DO NOTHING;

INSERT INTO "document_revisions" (
  "tenant_id",
  "knowledge_space_id",
  "document_id",
  "revision",
  "document_asset_id",
  "document_asset_version",
  "compilation_attempt_id",
  "expected_active_revision",
  "expected_document_row_version",
  "content_hash",
  "mime_type",
  "size_bytes",
  "state",
  "system_metadata",
  "created_at",
  "activated_at"
)
SELECT
  space."tenant_id",
  asset."knowledge_space_id",
  asset."id",
  asset."version",
  asset."id",
  asset."version",
  NULL,
  NULL,
  0,
  asset."sha256",
  asset."mime_type",
  asset."size_bytes",
  'active',
  jsonb_build_object('provenance', asset."metadata"),
  asset."created_at",
  COALESCE(asset."updated_at", asset."created_at")
FROM "document_assets" asset
JOIN "knowledge_spaces" space ON space."id" = asset."knowledge_space_id"
ON CONFLICT ("tenant_id", "knowledge_space_id", "document_id", "revision") DO NOTHING;

UPDATE "logical_documents" document
SET
  "active_revision" = asset."version",
  "row_version" = CASE WHEN document."active_revision" IS NULL THEN document."row_version" + 1 ELSE document."row_version" END
FROM "document_assets" asset
WHERE document."id" = asset."id"
  AND document."knowledge_space_id" = asset."knowledge_space_id"
  AND document."active_revision" IS NULL;