"""SQLite database schema for XER MCP Server."""

SCHEMA_SQL = """
-- Projects
CREATE TABLE IF NOT EXISTS projects (
    proj_id TEXT PRIMARY KEY,
    proj_short_name TEXT NOT NULL,
    plan_start_date TEXT,
    plan_end_date TEXT,
    last_recalc_date TEXT,
    loaded_at TEXT NOT NULL DEFAULT (datetime('now'))
);

-- Activities
CREATE TABLE IF NOT EXISTS activities (
    task_id TEXT PRIMARY KEY,
    proj_id TEXT NOT NULL,
    wbs_id TEXT,
    task_code TEXT NOT NULL,
    task_name TEXT NOT NULL,
    task_type TEXT NOT NULL,
    target_start_date TEXT,
    target_end_date TEXT,
    act_start_date TEXT,
    act_end_date TEXT,
    total_float_hr_cnt REAL,
    driving_path_flag INTEGER DEFAULT 0,
    status_code TEXT,
    FOREIGN KEY (proj_id) REFERENCES projects(proj_id)
);

-- Relationships
CREATE TABLE IF NOT EXISTS relationships (
    task_pred_id TEXT PRIMARY KEY,
    task_id TEXT NOT NULL,
    pred_task_id TEXT NOT NULL,
    pred_type TEXT NOT NULL,
    lag_hr_cnt REAL DEFAULT 0,
    FOREIGN KEY (task_id) REFERENCES activities(task_id),
    FOREIGN KEY (pred_task_id) REFERENCES activities(task_id)
);

-- WBS (Work Breakdown Structure)
CREATE TABLE IF NOT EXISTS wbs (
    wbs_id TEXT PRIMARY KEY,
    proj_id TEXT NOT NULL,
    parent_wbs_id TEXT,
    wbs_short_name TEXT NOT NULL,
    wbs_name TEXT,
    FOREIGN KEY (proj_id) REFERENCES projects(proj_id),
    FOREIGN KEY (parent_wbs_id) REFERENCES wbs(wbs_id)
);

-- Calendars (internal use only)
CREATE TABLE IF NOT EXISTS calendars (
    clndr_id TEXT PRIMARY KEY,
    clndr_name TEXT NOT NULL,
    day_hr_cnt REAL,
    week_hr_cnt REAL
);

-- Indexes for performance
CREATE INDEX IF NOT EXISTS idx_activities_proj ON activities(proj_id);
CREATE INDEX IF NOT EXISTS idx_activities_wbs ON activities(wbs_id);
CREATE INDEX IF NOT EXISTS idx_activities_type ON activities(task_type);
CREATE INDEX IF NOT EXISTS idx_activities_critical ON activities(driving_path_flag)
    WHERE driving_path_flag = 1;
CREATE INDEX IF NOT EXISTS idx_activities_dates ON activities(target_start_date, target_end_date);
CREATE INDEX IF NOT EXISTS idx_relationships_task ON relationships(task_id);
CREATE INDEX IF NOT EXISTS idx_relationships_pred ON relationships(pred_task_id);
CREATE INDEX IF NOT EXISTS idx_wbs_parent ON wbs(parent_wbs_id);
CREATE INDEX IF NOT EXISTS idx_wbs_proj ON wbs(proj_id);
"""


def get_schema() -> str:
    """Return the complete SQLite schema."""
    return SCHEMA_SQL