#!/bin/sh

set -eu
# TODO: Make sensitive to failures. I don't want to miss appointments!
# TODO Ensure safe use of delimiters

err() {
  echo "❌ $1" >/dev/tty
}

if [ -z "${FZF_VCAL_USE_EXPORTED:-}" ]; then
  # Read configuration
  CONFIGFILE="$HOME/.config/fzf-vcal/config"
  if [ ! -f "$CONFIGFILE" ]; then
    err "Configuration '$CONFIGFILE' not found."
    exit 1
  fi
  # shellcheck source=/dev/null
  . "$CONFIGFILE"
  if [ -z "${ROOT:-}" ] || [ -z "${SYNC_CMD:-}" ] || [ -z "${COLLECTION_LABELS:-}" ]; then
    err "Configuration is incomplete."
    exit 1
  fi
  export ROOT
  export SYNC_CMD
  export COLLECTION_LABELS

  # Tools
  if command -v "fzf" >/dev/null; then
    FZF="fzf"
  else
    err "Did not find the command-line fuzzy finder fzf."
    exit 1
  fi
  export FZF

  if command -v "uuidgen" >/dev/null; then
    UUIDGEN="uuidgen"
  else
    err "Did not find the uuidgen command."
    exit 1
  fi
  export UUIDGEN

  if command -v "bat" >/dev/null; then
    CAT="bat"
  elif command -v "batcat" >/dev/null; then
    CAT="batcat"
  fi
  CAT=${CAT:+$CAT --color=always --style=numbers --language=md}
  CAT=${CAT:-cat}
  export CAT

  ### AWK SCRIPTS
  AWK_LINES=$(
    cat <<'EOF'
@@include src/awk/lines.awk
EOF
  )
  export AWK_LINES

  AWK_MERGE=$(
    cat <<'EOF'
@@include src/awk/merge.awk
EOF
  )
  export AWK_MERGE

  AWK_PARSE=$(
    cat <<'EOF'
@@include src/awk/parse.awk
EOF
  )
  export AWK_PARSE

  AWK_WEEKVIEW=$(
    cat <<'EOF'
@@include src/awk/weekview.awk
EOF
  )
  export AWK_WEEKVIEW

  AWK_DAYVIEW=$(
    cat <<'EOF'
@@include src/awk/dayview.awk
EOF
  )
  export AWK_DAYVIEW
  ### END OF AWK SCRIPTS
  FZF_VJOUR_USE_EXPORTED="yes"
  export FZF_VJOUR_USE_EXPORTED
fi

__load_approx_data() {
  find "$ROOT" -type f -name '*.ics' -print0 |
    xargs -0 -P0 \
      awk \
      -v collection_labels="$COLLECTION_LABELS" \
      "$AWK_LINES"
}

__load_weeks() {
  dates=$(awk -F'|' '{ print $2; print $3 }' "$APPROX_DATA_FILE")
  file_dates=$(mktemp)
  echo "$dates" | date --file="/dev/stdin" +"%s" >"$file_dates"
  awk "$AWK_MERGE" "$file_dates" "$APPROX_DATA_FILE"
  rm "$file_dates"
}

__show_day() {
  weeknr=$(date -d "$DISPLAY_DATE" +"%s")
  weeknr=$(((weeknr - 259200) / 604800)) # shift, because epoch origin is a Thursday
  files=$(grep "^$weeknr " "$WEEKLY_DATA_FILE" | cut -d " " -f 2-)
  # Find relevant files in list of week files
  sef=$({
    set -- $files
    for file in "$@"; do
      file="$ROOT/$file"
      awk \
        -v collection_labels="$COLLECTION_LABELS" \
        "$AWK_PARSE" "$file"
    done
  })
  if [ -n "$sef" ]; then
    today=$(date -d "$DISPLAY_DATE" +"%D")
    sef=$(echo "$sef" | while IFS= read -r line; do
      set -- $line
      starttime="$1"
      shift
      endtime="$1"
      shift
      fpath="$1"
      shift
      description=$(echo "$*" | sed 's/|/:/g') # we will use | as delimiter
      #
      daystart=$(date -d "$today 00:00:00" +"%s")
      dayend=$(date -d "$today 23:59:59" +"%s")
      line=""
      if [ "$starttime" -gt "$daystart" ] && [ "$starttime" -lt "$dayend" ]; then
        s=$(date -d "@$starttime" +"%H:%M")
      elif [ "$starttime" -le "$daystart" ] && [ "$endtime" -gt "$daystart" ]; then
        s="00:00"
      else
        continue
      fi
      if [ "$endtime" -gt "$daystart" ] && [ "$endtime" -lt "$dayend" ]; then
        e=$(date -d "@$endtime" +"%H:%M")
      elif [ "$endtime" -ge "$dayend" ] && [ "$starttime" -lt "$dayend" ]; then
        e="00:00"
      else
        continue
      fi
      echo "$s|$e|$fpath|$description"
    done)
  fi
  GREEN="\033[1;32m"
  OFF="\033[m"
  echo "|🗓️ $GREEN $(date -d "$DISPLAY_DATE" +"%a %e %b %Y")$OFF"
  echo ""
  (
    echo "$sef"
    seq 8 18 | sort -n
  ) | awk "$AWK_DAYVIEW"
}

__list() {
  weeknr=$(date -d "$DISPLAY_DATE" +"%s")
  weeknr=$(((weeknr - 259200) / 604800)) # shift, because epoch origin is a Thursday
  files=$(grep "^$weeknr " "$WEEKLY_DATA_FILE" | cut -d " " -f 2-)
  dayofweek=$(date -d "$DISPLAY_DATE" +"%u")
  delta=$((1 - dayofweek))
  startofweek=$(date -d "$DISPLAY_DATE -$delta days" +"%D")
  # loop over files
  sef=$({
    set -- $files
    for file in "$@"; do
      file="$ROOT/$file"
      awk \
        -v collection_labels="$COLLECTION_LABELS" \
        "$AWK_PARSE" "$file"
    done
  })
  if [ -n "$sef" ]; then
    sef=$(echo "$sef" | while IFS= read -r line; do
      set -- $line
      starttime="$1"
      shift
      endtime="$1"
      shift
      #fpath="$1"
      shift
      description="$*"
      for i in $(seq 0 7); do
        daystart=$(date -d "$startofweek +$i days 00:00:00" +"%s")
        dayend=$(date -d "$startofweek +$i days 23:59:59" +"%s")
        if [ "$starttime" -gt "$daystart" ] && [ "$starttime" -lt "$dayend" ]; then
          s=$(date -d "@$starttime" +"%H:%M")
          s="$s -"
        elif [ "$starttime" -le "$daystart" ] && [ "$endtime" -gt "$daystart" ]; then
          s="00:00 -"
        else
          continue
        fi
        if [ "$endtime" -gt "$daystart" ] && [ "$endtime" -lt "$dayend" ]; then
          e=$(date -d "@$endtime" +"%H:%M")
          e="- $e"
        elif [ "$endtime" -ge "$dayend" ] && [ "$starttime" -lt "$dayend" ]; then
          e="- 00:00"
        else
          continue
        fi
        echo "$i $s$e >$description"
      done
    done)
  fi
  sef=$({
    echo "$sef"
    seq 0 7
  } | sort -n)
  echo "$sef" | awk -v startofweek="$startofweek" "$AWK_WEEKVIEW"
  #seq -f "$startofweek +%g days" 0 6 |
  #  LC_ALL=c xargs -I {} date -d "{}" +"%a %e %b %Y"
}

if [ -z "${APPROX_DATA_FILE:-}" ]; then
  APPROX_DATA_FILE=$(mktemp)
  __load_approx_data >"$APPROX_DATA_FILE"
  export APPROX_DATA_FILE
fi
if [ -z "${WEEKLY_DATA_FILE:-}" ]; then
  WEEKLY_DATA_FILE=$(mktemp)
  __load_weeks >"$WEEKLY_DATA_FILE"
  export WEEKLY_DATA_FILE
fi

if [ "${1:-}" = "--day" ]; then
  DISPLAY_DATE="$2"
  echo "Jumping to day $DISPLAY_DATE!"
  selection=$(
    __show_day |
      $FZF \
        --reverse \
        --ansi \
        --no-sort \
        --no-input \
        --delimiter='|' \
        --with-nth='{2}' \
        --accept-nth='{1}' \
        --bind="backspace:first+accept"
  )
  if [ -n "$selection" ]; then
    fpath="$ROOT/$selection"
  fi
fi

if [ "${1:-}" = "--date" ]; then
  DISPLAY_DATE="$2"
  echo "Jumping to date $2!"
fi
DISPLAY_DATE=${DISPLAY_DATE:-today}
DISPLAY_DATE=$(date -d "$DISPLAY_DATE" +"%D")
DISPLAY_DATE_PREV=$(date -d "$DISPLAY_DATE -1 week" +"%D")
DISPLAY_DATE_NEXT=$(date -d "$DISPLAY_DATE +1 week" +"%D")

selection=$( (
  cat "$APPROX_DATA_FILE"
  yes " " | head -n 50
  __list
) |
  $FZF \
    --tac \
    --no-sort \
    --no-hscroll \
    --ellipsis='' \
    --delimiter='|' \
    --with-nth='{4}' \
    --accept-nth=1,2 \
    --no-info \
    --ansi \
    --no-clear \
    --bind="ctrl-p:become($0 --date '$DISPLAY_DATE_PREV')" \
    --bind="ctrl-n:become($0 --date '$DISPLAY_DATE_NEXT')" \
    --bind="ctrl-l:become($0)")

if [ -z "$selection" ]; then
  rm "$WEEKLY_DATA_FILE" "$APPROX_DATA_FILE"
  return 0
fi

sign=$(echo "$selection" | cut -d '|' -f 1)
startdate=$(echo "$selection" | cut -d '|' -f 2)
if [ "$sign" = "~" ]; then
  exec $0 --date "$startdate"
else
  exec $0 --day "$startdate"
fi
echo "Going to end..."
echo "$selection"
echo "STOPPING NOW"