#!/usr/bin/env bash
# Regression harness for detect-platform.sh's get_gitea_token() per-agent
# identity resolution (Gate-16 author≠reviewer separation) — the API-tooling
# counterpart to git-credential-mosaic, so pr-create.sh/issue-create.sh/etc.
# open records under the resolved agent identity, not the shared account.
#
# Covers:
#   1. Identity resolution priority: MOSAIC_GIT_IDENTITY env > git config
#      mosaic.gitIdentity (per-worktree).
#   2. Correct per-slot token file path chosen per host
#      (gitea-usc-<id>.token vs gitea-mosaicstack-<id>.token).
#   3. Per-slot token present -> that token is returned (agent-authored calls).
#   4. Per-slot token absent -> falls back to the shared credential-loader
#      token (backward-compat / no-op for hosts without per-slot tokens).
#   5. Unrelated host with no shared credentials configured -> failure
#      (unchanged, existing behavior).
#
# Uses a stubbed credentials.json + stubbed per-slot token files under a fake
# HOME. NEVER reads real secrets or touches the real ~/.config/mosaic/secrets.

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
WORK_DIR="${MOSAIC_TEST_WORK_DIR:-$PWD/.mosaic-test-work/gitea-token-identity}"
FAKE_HOME="$WORK_DIR/home"
REPO_DIR="$WORK_DIR/repo"
CREDENTIALS_FILE="$FAKE_HOME/.config/mosaic/credentials.json"

rm -rf "$WORK_DIR"
mkdir -p "$FAKE_HOME/.config/mosaic/secrets/gitea-tokens" "$REPO_DIR"

git -C "$REPO_DIR" init -q
git -C "$REPO_DIR" remote add origin https://git.mosaicstack.dev/mosaicstack/stack.git

cat > "$CREDENTIALS_FILE" <<'JSON'
{
  "gitea": {
    "mosaicstack": {
      "url": "https://git.mosaicstack.dev",
      "token": "shared-mosaicstack-token"
    },
    "usc": {
      "url": "https://git.uscllc.com",
      "token": "shared-usc-token"
    }
  }
}
JSON

fail=0
assert_eq() {
  local desc="$1" expected="$2" actual="$3"
  if [[ "$expected" != "$actual" ]]; then
    echo "FAIL: $desc — expected '$expected', got '$actual'" >&2
    fail=1
  fi
}

# Runs get_gitea_token for $1=host inside REPO_DIR (per-worktree git config
# resolves there) with a fake HOME + the stub credentials.json, plus any
# extra env passed in $@.
call_get_gitea_token() {
  local host="$1"; shift
  (
    cd "$REPO_DIR"
    # shellcheck disable=SC2016 # deliberately deferred: $DETECT_PLATFORM_SH is
    # expanded by the INNER bash -c (via the exported env var below), not here.
    env -i HOME="$FAKE_HOME" PATH="$PATH" MOSAIC_CREDENTIALS_FILE="$CREDENTIALS_FILE" \
      DETECT_PLATFORM_SH="$SCRIPT_DIR/detect-platform.sh" "$@" \
      bash -c 'source "$DETECT_PLATFORM_SH"; get_gitea_token "$1"' _ "$host"
  )
}

# ---------------------------------------------------------------------------
# 1. No identity resolvable -> shared credential-loader token (unchanged).
# ---------------------------------------------------------------------------
git -C "$REPO_DIR" config --unset mosaic.gitIdentity 2>/dev/null || true
out=$(call_get_gitea_token "git.mosaicstack.dev")
assert_eq "shared fallback (no identity)" "shared-mosaicstack-token" "$out"

# ---------------------------------------------------------------------------
# 2. git config mosaic.gitIdentity resolves to an agent WITH a per-slot
#    token -> that token wins over the shared account.
# ---------------------------------------------------------------------------
echo -n "agentA-mosaicstack-token" > "$FAKE_HOME/.config/mosaic/secrets/gitea-tokens/gitea-mosaicstack-agentA.token"
git -C "$REPO_DIR" config mosaic.gitIdentity agentA
out=$(call_get_gitea_token "git.mosaicstack.dev")
assert_eq "git-config identity token" "agentA-mosaicstack-token" "$out"

# ---------------------------------------------------------------------------
# 3. MOSAIC_GIT_IDENTITY env beats git config mosaic.gitIdentity.
# ---------------------------------------------------------------------------
echo -n "agentB-mosaicstack-token" > "$FAKE_HOME/.config/mosaic/secrets/gitea-tokens/gitea-mosaicstack-agentB.token"
out=$(call_get_gitea_token "git.mosaicstack.dev" MOSAIC_GIT_IDENTITY=agentB)
assert_eq "env beats git-config identity token" "agentB-mosaicstack-token" "$out"

# ---------------------------------------------------------------------------
# 4. Identity resolves but has no per-slot token for THIS host -> falls back
#    to the shared token (per-agent identity is opt-in per host).
# ---------------------------------------------------------------------------
git -C "$REPO_DIR" config mosaic.gitIdentity no-such-agent
out=$(call_get_gitea_token "git.mosaicstack.dev")
assert_eq "no per-slot token falls back to shared" "shared-mosaicstack-token" "$out"

# ---------------------------------------------------------------------------
# 5. Correct per-slot token PATH per host: same agent id, only a usc token
#    exists -> usc host returns it, mosaicstack host must NOT leak it and
#    instead falls back to the shared mosaicstack token.
# ---------------------------------------------------------------------------
echo -n "agentD-usc-token" > "$FAKE_HOME/.config/mosaic/secrets/gitea-tokens/gitea-usc-agentD.token"
git -C "$REPO_DIR" config mosaic.gitIdentity agentD
out=$(call_get_gitea_token "git.uscllc.com")
assert_eq "host-scoped token path (usc)" "agentD-usc-token" "$out"
out=$(call_get_gitea_token "git.mosaicstack.dev")
assert_eq "host-scoped token path (no cross-host leak)" "shared-mosaicstack-token" "$out"
git -C "$REPO_DIR" config --unset mosaic.gitIdentity

if [[ "$fail" -eq 0 ]]; then
  echo "get_gitea_token identity resolution regression passed"
fi

exit "$fail"