-- 005: Issue workspace-level upgrade + slug removal
-- 1. Drop slug from workspace
-- 2. Lift issue from repo-level to workspace-level (repo_id -> workspace_id)
-- 3. Add issue_repo_relation for multi-repo association
-- 4. Add milestone_id to issue
-- 5. Add missing unique constraints

ALTER TABLE workspace DROP COLUMN IF EXISTS slug;
CREATE UNIQUE INDEX IF NOT EXISTS uq_workspace_name ON workspace (lower(name)) WHERE deleted_at IS NULL;

DROP INDEX IF EXISTS idx_issue_repo_id;
DROP INDEX IF EXISTS idx_issue_repo_created;

ALTER TABLE issue DROP CONSTRAINT IF EXISTS issue_repo_id_fkey;

DO $$
    BEGIN
        IF EXISTS (
            SELECT 1
            FROM information_schema.columns
            WHERE table_schema = 'public'
              AND table_name = 'issue'
              AND column_name = 'repo_id'
        )
            AND NOT EXISTS (
                SELECT 1
                FROM information_schema.columns
                WHERE table_schema = 'public'
                  AND table_name = 'issue'
                  AND column_name = 'workspace_id'
            ) THEN
            ALTER TABLE issue RENAME COLUMN repo_id TO workspace_id;
        END IF;
    END $$;

DO $$
    BEGIN
        IF NOT EXISTS (
            SELECT 1
            FROM pg_constraint
            WHERE conname = 'issue_workspace_id_fkey'
              AND conrelid = 'issue'::regclass
        ) THEN
            ALTER TABLE issue
                ADD CONSTRAINT issue_workspace_id_fkey
                    FOREIGN KEY (workspace_id) REFERENCES workspace(id) ON DELETE CASCADE;
        END IF;
    END $$;

CREATE INDEX IF NOT EXISTS idx_issue_workspace_id ON issue (workspace_id);
CREATE INDEX IF NOT EXISTS idx_issue_ws_created ON issue (workspace_id, created_at DESC);

DO $$
    BEGIN
        IF NOT EXISTS (
            SELECT 1
            FROM pg_constraint
            WHERE conname = 'uq_issue_workspace_number'
              AND conrelid = 'issue'::regclass
        ) THEN
            ALTER TABLE issue
                ADD CONSTRAINT uq_issue_workspace_number UNIQUE (workspace_id, number);
        END IF;
    END $$;

CREATE TABLE IF NOT EXISTS issue_repo_relation (
                                                   id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
                                                   issue_id UUID NOT NULL REFERENCES issue(id) ON DELETE CASCADE,
                                                   repo_id UUID NOT NULL REFERENCES repo(id) ON DELETE CASCADE,
                                                   relation_type TEXT NOT NULL,
                                                   created_by UUID NULL REFERENCES "user"(id) ON DELETE CASCADE,
                                                   created_at TIMESTAMPTZ NOT NULL,
                                                   CONSTRAINT uq_issue_repo_relation UNIQUE (issue_id, repo_id)
);

CREATE INDEX IF NOT EXISTS idx_issue_repo_relation_issue_id
    ON issue_repo_relation (issue_id);

CREATE INDEX IF NOT EXISTS idx_issue_repo_relation_repo_id
    ON issue_repo_relation (repo_id);

ALTER TABLE issue
    ADD COLUMN IF NOT EXISTS milestone_id UUID NULL REFERENCES issue_milestone(id) ON DELETE SET NULL;

CREATE INDEX IF NOT EXISTS idx_issue_milestone_id ON issue (milestone_id);

DO $$
    BEGIN
        IF NOT EXISTS (
            SELECT 1
            FROM pg_constraint
            WHERE conname = 'uq_issue_label_relation'
              AND conrelid = 'issue_label_relation'::regclass
        ) THEN
            ALTER TABLE issue_label_relation
                ADD CONSTRAINT uq_issue_label_relation UNIQUE (issue_id, label_id);
        END IF;
    END $$;
CREATE UNIQUE INDEX IF NOT EXISTS uq_repo_workspace_name
    ON repo (workspace_id, lower(name)) WHERE deleted_at IS NULL;

-- ─── 7. pull_request: unique number per repo ───────────────────────────
DO $$
    BEGIN
        IF NOT EXISTS (
            SELECT 1 FROM pg_constraint
            WHERE conname = 'uq_pull_request_repo_number' AND conrelid = 'pull_request'::regclass
        ) THEN
            ALTER TABLE pull_request
                ADD CONSTRAINT uq_pull_request_repo_number UNIQUE (repo_id, number);
        END IF;
    END $$;

-- ─── 8. pr_label_relation: unique constraint ────────────────────────────
DO $$
    BEGIN
        IF NOT EXISTS (
            SELECT 1 FROM pg_constraint
            WHERE conname = 'uq_pr_label_relation' AND conrelid = 'pr_label_relation'::regclass
        ) THEN
            ALTER TABLE pr_label_relation
                ADD CONSTRAINT uq_pr_label_relation UNIQUE (pull_request_id, label_id);
        END IF;
    END $$;