-- Migration 002: Issue Ingestion Tables
-- Applies on top of 001_initial.sql

-- Issues table
CREATE TABLE issues (
    id INTEGER PRIMARY KEY,
    gitlab_id INTEGER UNIQUE NOT NULL,
    project_id INTEGER NOT NULL REFERENCES projects(id) ON DELETE CASCADE,
    iid INTEGER NOT NULL,
    title TEXT,
    description TEXT,
    state TEXT NOT NULL CHECK (state IN ('opened', 'closed')),
    author_username TEXT,
    created_at INTEGER NOT NULL,           -- ms epoch UTC
    updated_at INTEGER NOT NULL,           -- ms epoch UTC
    last_seen_at INTEGER NOT NULL,         -- updated on every upsert
    discussions_synced_for_updated_at INTEGER, -- watermark for dependent sync
    web_url TEXT,
    raw_payload_id INTEGER REFERENCES raw_payloads(id)
);

CREATE INDEX idx_issues_project_updated ON issues(project_id, updated_at);
CREATE INDEX idx_issues_author ON issues(author_username);
CREATE UNIQUE INDEX uq_issues_project_iid ON issues(project_id, iid);

-- Labels table (name-only for CP1)
CREATE TABLE labels (
    id INTEGER PRIMARY KEY,
    gitlab_id INTEGER,                      -- optional, for future Labels API
    project_id INTEGER NOT NULL REFERENCES projects(id) ON DELETE CASCADE,
    name TEXT NOT NULL,
    color TEXT,
    description TEXT
);

CREATE UNIQUE INDEX uq_labels_project_name ON labels(project_id, name);
CREATE INDEX idx_labels_name ON labels(name);

-- Issue-label junction (DELETE before INSERT for stale removal)
CREATE TABLE issue_labels (
    issue_id INTEGER NOT NULL REFERENCES issues(id) ON DELETE CASCADE,
    label_id INTEGER NOT NULL REFERENCES labels(id) ON DELETE CASCADE,
    PRIMARY KEY(issue_id, label_id)
);

CREATE INDEX idx_issue_labels_label ON issue_labels(label_id);

-- Discussion threads for issues (MR discussions added in CP2)
CREATE TABLE discussions (
    id INTEGER PRIMARY KEY,
    gitlab_discussion_id TEXT NOT NULL,     -- GitLab string ID (e.g., "6a9c1750b37d...")
    project_id INTEGER NOT NULL REFERENCES projects(id) ON DELETE CASCADE,
    issue_id INTEGER REFERENCES issues(id) ON DELETE CASCADE,
    merge_request_id INTEGER,               -- FK added in CP2 via ALTER TABLE
    noteable_type TEXT NOT NULL CHECK (noteable_type IN ('Issue', 'MergeRequest')),
    individual_note INTEGER NOT NULL DEFAULT 0,  -- 0=threaded, 1=standalone
    first_note_at INTEGER,                  -- min(note.created_at) for ordering
    last_note_at INTEGER,                   -- max(note.created_at) for "recently active"
    last_seen_at INTEGER NOT NULL,          -- updated on every upsert
    resolvable INTEGER NOT NULL DEFAULT 0,  -- MR discussions can be resolved
    resolved INTEGER NOT NULL DEFAULT 0,
    CHECK (
        (noteable_type = 'Issue' AND issue_id IS NOT NULL AND merge_request_id IS NULL) OR
        (noteable_type = 'MergeRequest' AND merge_request_id IS NOT NULL AND issue_id IS NULL)
    )
);

CREATE UNIQUE INDEX uq_discussions_project_discussion_id ON discussions(project_id, gitlab_discussion_id);
CREATE INDEX idx_discussions_issue ON discussions(issue_id);
CREATE INDEX idx_discussions_mr ON discussions(merge_request_id);
CREATE INDEX idx_discussions_last_note ON discussions(last_note_at);

-- Notes belong to discussions
CREATE TABLE notes (
    id INTEGER PRIMARY KEY,
    gitlab_id INTEGER UNIQUE NOT NULL,
    discussion_id INTEGER NOT NULL REFERENCES discussions(id) ON DELETE CASCADE,
    project_id INTEGER NOT NULL REFERENCES projects(id) ON DELETE CASCADE,
    note_type TEXT,                         -- 'DiscussionNote' | 'DiffNote' | null
    is_system INTEGER NOT NULL DEFAULT 0,   -- 1 for system-generated notes
    author_username TEXT,
    body TEXT,
    created_at INTEGER NOT NULL,            -- ms epoch
    updated_at INTEGER NOT NULL,            -- ms epoch
    last_seen_at INTEGER NOT NULL,          -- updated on every upsert
    position INTEGER,                       -- 0-indexed array order from API
    resolvable INTEGER NOT NULL DEFAULT 0,
    resolved INTEGER NOT NULL DEFAULT 0,
    resolved_by TEXT,
    resolved_at INTEGER,
    -- DiffNote position metadata (populated for MR DiffNotes in CP2)
    position_old_path TEXT,
    position_new_path TEXT,
    position_old_line INTEGER,
    position_new_line INTEGER,
    raw_payload_id INTEGER REFERENCES raw_payloads(id)
);

CREATE INDEX idx_notes_discussion ON notes(discussion_id);
CREATE INDEX idx_notes_author ON notes(author_username);
CREATE INDEX idx_notes_system ON notes(is_system);

-- Update schema version
INSERT INTO schema_version (version, applied_at, description)
VALUES (2, strftime('%s', 'now') * 1000, 'Issue ingestion tables');